This article is in response to Burning off the answer to intensity by Philip Hopkins, published in the Latrobe Valley Express on 19 March 2025 and on Australian Rural & Regional News on 25 March 2025. Find many more articles on this topic at Open for Debate: Bushfires, Logging, Burns & Forest Management.
Professor David Lindenmayer AO and Associate-Professor Philip Zylstra, Fenner School of Environment and Society, The Australian National University.
Dr Tony Bartlett’s recent article in the Latrobe Valley Express contains serious flaws in logic and misrepresents scientific evidence. Understanding the empirical data is critical for safeguarding communities and preserving native species.
Logging and flammability: what the science says
Tony Bartlett claims there is no evidence that logged forests are more flammable. This is demonstrably false. Robust peer-reviewed research shows logged and regenerated forests are (statistically) significantly more likely to burn at higher severity than intact forests. University of Wollongong studies found that this elevated flammability persists for 70 years (Wilson et al. 2022). A study of the Black Summer 2019-202 wildfires in mainland eastern Australia showed logged forests always burnt at higher severity than intact forests (Lindenmayer et al. 2022b). This effect was seen in forests in north-eastern Victoria, south-eastern NSW, and northern NSW. Importantly, logged forests burning under moderate fire weather conditions still burnt at greater severity than intact forests burning under extreme conditions (Lindenmayer et al. 2022b). This underscores how logging increases fire risk and flammability (Lindenmayer et al. 2022b).
Research in Tasmania’s forests (Furlaud et al. 2021) as well as international studies from the USA, Canada, Asia and South America (Thompson et al. 2007) (Levine et al. 2022) show similar outcomes. The term “disturbance-stimulated flammability” is now used to describe how logging and thinning operations increase fire risk. It is important to note that logging effects on fire risks are seen in forests where logging occurs; logging effects are not seen where logging does not occur (such as in Snow Gum). Tony Bartlett’s argument—that fire severity is the same in logged State Forests with unlogged National Parks (where logging does not occur)—is nonsensical. It is clear that there is an increasing body of rigorous scientific evidence about relationships between logging and fire risk.
In the face of climate change and increasing fire weather, any land use that elevates flammability and endangers human communities, like widespread logging, needs to be reconsidered.
Prescribed burning: complex and context-dependent
Tony Bartlett sings the praises of widespread prescribed burning, but provides no robust empirical evidence of its effectiveness. Evidence to date shows that prescribed burning leads to a small reduction in house loss and property damage, but only when applied close to assets and within the previous few years (Gibbons et al. 2012).
In fact, prescribed burning can have unintended long-term effects and Tony Bartlett fails to mention them:
- In Western Australia, prescribed burning reduced flammability in the short-term, but increased it for decades later (Zylstra et al. 2022).
- Research by Price et al. (2022) in south-eastern Australia found forests burned 5-6 years earlier were more prone to high-severity fire.
- In forests of the Sydney – Blue Mountains and Illawarra area, crown fire was virtually absent in areas unburned for 30 years (Barker and Price 2018).
Prescribed burning in remote forests can be counter-productive and actually make some ecosystems MORE flammable, not less (Dixon et al. 2018, Zylstra et al. 2022). Furthermore, prescribed fires may have limited effectiveness under the extreme fire weather driven by a changing climate (Calkin et al. 2023).
Tony Bartlett also fails to mention other significant negative impacts of prescribed burning.
First, some ecosystems—such as the tall, wet forests of Victoria—the natural fire regime is rare, high-severity wildfire. Introducing prescribed burns to these ecosystems is totally inappropriate and would lead to their collapse (Lindenmayer et al. 2024).
Second, there have been numerous cases of prescribed burns destroying homes and property. Examples include incidents on Sydney’s northern beaches, in Margaret River in Western Australia, and, most recently, the loss of valuable vineyards due to a hazard reduction burn (https://www.abc.net.au/news/2025-03-26/winemaker-says-hazard-reduction-burn-destroyed-grapes/105096772).
Third, prescribed burning generates vast amounts of smoke, which poses serious public health risks. Smoke from prescribed burns in Sydney led to 14 premature deaths (Vardoulakis et al. 2020). Many of these areas later burned again in the 2019 Gospers Mountain fire, as mentioned by Tony Bartlett, but a report conducted for the Bushfire and Natural Hazards CRC found that high severity fire was more likely in areas burned 5-6 years earlier than it was in long-unburnt areas (Price et al. 2022). As a result, smoke from those same blocks enhanced the impact from the Gospers Mountain fire. Similarly, in south-west Western Australia, prescribed burn smoke between 2002 and 2017 led to an estimated 21 deaths—five times more than wildfire deaths in the same period, which totalled four.
Fourth, there are negative impacts on biodiversity. A major Nature study showed that when the condition of ecosystems was altered by prior disturbances, such as repeated prescribed burning, the recovery of biodiversity following the 2019-2020 wildfires was severely impaired (Driscoll and al. 2024). In fact, for many species, the number of previous fires (including prescribed fires) had far greater effects than the severity of a single fire in 2019-2020. Notably, our long-term empirical research on fire effects in Booderee National Park showed that bird species richness in an area was reduced by 9.1 per cent for every additional fire that occurred (dating back to 1972) (Lindenmayer et al. 2008). In Western Australia, prescribed burning killed 77 per cent of the population of the Critically Endangered Western Ringtail Possum (or ngwayir) (Zylstra 2023).
Are there alternatives?
Yes. One approach is to assist ecosystems to exert their own natural ecological controls on fire. This is to enable the return of natural fire regimes, even in a changing climate. Elements of plant growth and succession can encourage some types of forest to develop environments that are less fire-prone (Zylstra et al. 2023). Taller trees and sub-canopy plants that self-prune shaded branches are less likely to ignite and more likely to slow wind speeds beneath them during fires (Lindenmayer and Zylstra 2024). As the forest biomass increases in height, lower vegetation becomes more moist and more sparse, reducing the spread of ground-layer fire (Zylstra et al. 2023). Even in relatively dry environments such as south-western Australia, historical records show that allowing forests to mature for several decades without fire has the same hazard reduction effectiveness as annual prescribed burning (Zylstra et al. 2024). In addition, there are important opportunities to embrace new technologies to more quickly detect and then more rapidly suppress ignitions – and before they become large wildfires that are difficult to control (Lindenmayer et al. 2022a).
Lived experience vs scientific evidence
Tony Bartlett talks about the “lived experience” and wildfires. But the lived experience in 1450 told us that the Earth was the centre of the universe. Science proved otherwise. Today, a growing body of rigorous scientific evidence shows that both logging and, in some cases, prescribed burning, increases fire risk. In addition, widespread prescribed burning can have perverse impacts on the environment, human health, and even future fire risks. We cannot afford to ignore this scientific information. In an era of rapid climate change and increasing bushfire threates, science must guide fire management—not assumptions or outdated practices.
References
– Barker, J. W., and O. F. Price. 2018. Positive severity feedback between consecutive fires in dry eucalypt forests of southern Australia. Ecosphere 9:e02110.
– Calkin, D. E., K. Barrett, J. D. Cohen, M. A. Finney, S. J. Pyne, and S. L. Quarles. 2023. Wildland-urban fire disasters aren’t actually a wildfire problem. Proceedings of the National Academy of Sciences 120:e2315797120.
– Dixon, K. M., G. Cary, G. L. Worboys, J. Seddon, and P. Gibbons. 2018. A comparison of fuel hazard in recently burned and long-unburned forests and woodlands. International Journal of Wildland Fire 27:609-622.
– Driscoll, D. A., and e. al. 2024. Biodiversity impacts of the 2019–2020 Australian megafires. Nature.
– Furlaud, J. M., L. D. Prior , G. J. Williamson , and D. M. J. S. Bowman. 2021. Fire risk and severity decline with stand development in Tasmanian giant Eucalyptus forest. Forest Ecology and Management 502:119724.
– Gibbons, P., L. van Bommel, A. M. Gill, G. J. Cary, D. A. Driscoll, A. Ross, R. A. Bradstock, E. Knight, M. A. Moritz, S. L. Stephens, and D. B. Lindenmayer. 2012. Land management practices associated with house loss in wildfires. PLOS One 7:e29212.
– Levine, J. I., B. M. Collins, Z. Steel, P. de Valpine, and S. L. Stephens. 2022. Higher incidence of high-severity fire in and near industrially managed forests. Frontiers in Ecology and Environment 20:398-404.
– Lindenmayer, D., P. Zylstra, and M. Yebra. 2022a. Adaptive wildfire mitigation approaches. Science 377:1163-1164.
– Lindenmayer, D. B., C. Taylor, E. Bowd, and P. Zylstra. 2024. What did it used to look like? A case study from tall, wet mainland Mountain Ash forests prior to British Invasion. Austral Ecology 49:e13520
– Lindenmayer, D. B., J. T. Wood, R. B. Cunningham, C. MacGregor, M. Crane, D. Michael, R. Montague-Drake, D. Brown, R. Muntz, and A. M. Gill. 2008. Testing hypotheses associated with bird responses to wildfire. Ecological Applications 18:1967-1983.
– Lindenmayer, D. B., and P. Zylstra. 2024. Identifying and managing disturbance-stimulated flammability in woody ecosystems. Biological Reviews 99:699–714.
– Lindenmayer, D. B., P. Zylstra, R. Kooyman, C. Taylor, M. Ward, and J. E. M. Watson. 2022b. Logging elevated the probability of high-severity fire in the 2019–20 Australian forest fires. Nature Ecology & Evolution 6:533-535.
– Price, O. F., J. W. Barker, S. Rahmani, C. Wilkinson, and D. Macdonald. 2022. Analysis and characterisation of bushfire-meets-prescribed burn events from the 2019-20 fire season.
– Thompson, J. R., T. A. Spies, and L. M. Ganio. 2007. Reburn severity in managed and unmanaged vegetation in a large wildfire. Proceedings of the National Academy of Sciences 104:10743-10748.
– Vardoulakis, S., B. B. Jalaludin, G. G. Morgan, I. C. Hanigan, and F. H. Johnston. 2020. Bushfire smoke: urgent need for a national health protection strategy. Medical Journal of Australia 212:349-353.
– Wilson, N., R. Bradstock, and M. Bedward. 2022. Disturbance causes variation in sub-canopy fire weather conditions. Agricultural and Forest Entomology 323:109077.
– Zylstra, P. 2023. Quantifying the direct fire threat to a critically endangered arboreal marsupial using biophysical, mechanistic modelling. Austral Ecology 48:266-238.
– Zylstra, P., D. Bradshaw, and D. B. Lindenmayer. 2022. Self-thinning forest understoreys reduce wildfire risk, even in a warming climate. Environment Research Letters 17:044022.
– Zylstra, P. J., S. D. Bradshaw, and D. B. Lindenmayer. 2024. Reply to comment on ‘Self-thinning forest understoreys reduce wildfire risk, even in a warming climate. Environment Research Letters 19:058001
– Zylstra, P. J., G. W. Wardell-Johnson, D. S. Falster, M. Howe, N. McQuoid, and S. Neville. 2023. Mechanisms by which growth and succession limit the impact of fire in a south-western Australian forested ecosystem. Functional Ecology 37:1350–1365.
Very sorry to see ARRNews giving space and lending credence to what can only be described as pathological science. Definitely no longer on my reading list ARR News.
https://forestfirevictoria.org.au/wp-content/uploads/2020/10/HODGSON-Managing-hazardous-bushfires-1.pdf?fbclid=IwZXh0bgNhZW0CMTEAAR6YXUOuNXAlZ_vDKugsoMQ0yoinxH-prW-bgvXjIdi9WRrphb3FmO5ZLDHFlw_aem_upzbYUtjOag0jSOgb0Eyuw
I believe articles like the one above are important as they provide the opportunity for people to respond and highlight the flaws in the arguments of anti-fire people like Lindenmayer. Apologies for the long reply but I’d welcome responses:
1. When Lindenmayer and others talk about ‘logging’ in the forests of eastern Australia, they’re actually talking about clearfelling, not selective logging. I have always believed that clearfelling of forests (other than karri and mountain ash which are effectively clearfelled every 200 or so years by catastrophic fire) is wrong for ecological reasons. Such clearfelling simply does not occur in WA and, to the best of my knowledge, has never occurred. As a result, when people discuss prescribed burning and consider Lindenmayer’s views, we are talking about two entirely different types of post-logging landscapes – what happens in WA and what happens in many SE Australian forests.
[Edited]
3. People in Victoria are critical of the 5% of forest that government authorities try to burn each year. While I agree that a simple goal of a set amount of land to be burnt every year is undesirable, the problem is that you’re dealing with a state government agency that is funded by state government to do a particular job. If less than 5% is burnt in a particular year and the full budget amount isn’t spent as a result, it’s likely the agency’s budget will be cut the following year, with finance bureaucrats and politicians claiming the fire agency clearly doesn’t need to burn 5% each year. If they burn more than 5% in a year, the same bureaucrats and politicians will say the agency doesn’t need as much money since they can burn more than 5% with the budgeted money, so a cut-back in funding is appropriate. In other words, the fire agency MUST burn 5% each year AND must spend its full budget allocation each year or else it will get less money the following year. Until the public offers public support to fire agencies on the basis that they must have the flexibility to burn better with a guaranteed annual financial budget, then the current funding versus 5% area target problems will continue.
4. Here in WA, one of the legitimate complaints is that prescribed burns often burn fire-sensitive environments. To stop this happening, WA’s fire agencies need more funding so that they can go out into our forests and burn more carefully etc. However, activists [edited] never call for more funding to allow this higher quality management to occur, instead just complaining about what is happening now and offering no practical, safe, effective alternatives.
5. As for alternatives, Zylstra, Lindenmayer and their supporters call for the adoption of a ‘rapid detection and rapid suppression’ fire policy, but there is nowhere in the world that such a policy exists. In WA, the policy is a combination of prescribed burning COMBINED WITH rapid detection/suppression, with fire agencies knowing that many/most fires cannot be suppressed quickly, even if they are detected quickly. To give just one example, in March 2022, my wife and I were camped in state forest east of Bunbury and, on the night after a 40 degree C day, two bands of thunderstorms went through and we awoke to 17 fires burning in the south west. Fortunately, all but one were burning in low fuel areas, so 16 fires could be safely left alone while the one serious fire was targeted. If we adopt the highly dangerous no fire policy of Zylstra and others, all 17 fires would have been burning in high fuel areas, totally overwhelming the state’s fire fighting capabilities.
8. A basic point that Lindenmayer, Zylstra and others ignore is that fire = growth of understorey = biodiversity! Without fire, Australia’s unique diversity of plants and wildlife would be adversely affected, leading to multiple species’ extinctions
Thanks for publishing both sides of this debate about the science of burning forests.
It’s especially refreshing to see research and evidence presented that makes logical sense.
I think having an understanding of ecological processes is key. From what I’ve observed over the years, both as a CFA vollie and having been a keen observer of natural processes, the most recent oeer reviewed science by Zylstra and Lindenmayer is extremely important to be considered. Let’s hope our state Fire Agencies step out of the past century and begin to incorporate this new research that can only help keep us all safer.